This application claims priority of prior, provisional patent application Ser. No. 60/224,632, filed Aug. 11, 2001, and also claims priority of prior, provisional patent application Ser. No. 60/272,221, filed Feb. 27, 2001, which are herein incorporated by this reference.
This invention relates generally to fluid filters and filter cartridges and connections for the filters/cartridges to piping, valving, brackets, and other holders that cooperate with the filters/cartridges to make them operative in a flowing fluid system. More specifically, this invention relates to a system for xe2x80x9ckeyingxe2x80x9d a particular filter cartridge or filter to a particular cooperating filter head member or filter valve head.
The invention is an apparatus and method wherein a portion of a fluid cartridge-holder connection is structurally adapted so that only matched filter cartridges and holders can cooperate to allow installation of the filter cartridge in the holder and/or to form a fluid seal. In other words, each filter cartridge and holder combination or xe2x80x9csetxe2x80x9d is xe2x80x9ckeyedxe2x80x9d so that only that particular filter cartridge design mates with that holder. According to the invention, there are created various cartridge-holder sets that each have the adaptation, but the adaptation is slightly offset for each set compared to the other sets. This way, a filter cartridge from one set may not be mixed with a cartridge from another set, and, therefore, a filter cartridge may not be installed on any but its own matching holder.
The adaptation preferably involves a varying location of a xe2x80x9ckeyxe2x80x9d protrusion and a xe2x80x9clockxe2x80x9d recess combination, such as a tab-slot combination, typically with mating protrusion(s) and recess(es) being at a certain angle on a circumference for one cartridge-holder set and a mating protrusion(s) and recess(s) of a similar or identical shape being at a different angle on the circumference for another cartridge-holder set, and so on, for each similarly-shaped-but-differently-located-adaptation cartridge and holder set. In other words, the key protrusion and the lock recess are selectably locateable around cooperating perimeters of a filter cartridge and its holder. The key and lock structures (hereafter typically called xe2x80x9ckey protrusionxe2x80x9d or xe2x80x9cprotrusionxe2x80x9d and xe2x80x9clock recessxe2x80x9d or xe2x80x9crecessxe2x80x9d, respectively) are preferably rigidly molded or otherwise permanently placed on/in the filter cartridge and holder, and so they are not considered moveable. They are, however, easily changed in the molding or other manufacturing process, that is, they are easily selectable by locating them at different angles/locations around a circumferential surface.
This system may include a plurality of sets of filters and holders, each set having a differently-located key and lock, wherein the key and lock of each set cooperate with each other to allow that filter to be installed in that holder, but that filter may not be installed in any other holder because the key or lock of that filter does not cooperate with the key or lock of the other holder. The term xe2x80x9ckey or lockxe2x80x9d is used because the key protrusions may be placed on either the filter or the holder, and the lock recess may therefore be placed on the other item.
Thus, for example, a water or beverage filtration facility, experimental pilot plant, or other filter user may control filter cartridge placement accurately. A facility with multiple, different filtering applications may have filter cartridges on hand for each of the applications, but the cartridges will not be confused. For example, in a facility in which there are two different applications, many of the two different types of filter cartridges may be kept in stock and even may be mixed during storage or handling, but the filter cartridges will not be mixed when installed into the filter holders. This is because the filter holder and the filter cartridges for the first application are xe2x80x9ckeyedxe2x80x9d differently than the filter holder and the filter cartridges for the second application. The terms xe2x80x9ckeyingxe2x80x9d or xe2x80x9ckeyedxe2x80x9d refer generally to how and where the entire key system is located or accomplished, that is, to the positioning or style of either one or both of the cooperating key and lock structures, rather than specifically to only the location of the xe2x80x9ckey protrusion.xe2x80x9d All the filter cartridges for the first application are keyed the same, that is, to match the first application holder, and all the filter cartridges for the second application are keyed the same, to match the second application holder. The keying for the first application and the keying for the second application does not need to be very different, but may be merely, for example, a slightly different angular position for the two protrusions and recesses.
Also, a filter manufacturer may control his product lines more carefully by using the invented key system. A manufacturer may key his holders and filter cartridges differently for different countries, different clients, different distributors, or for different time periods. This technique may be used to prevent unauthorized or low-quality copies of the manufacturer""s filter cartridges from easily being made. With so many differently-keyed cartridges in the marketplace provided by the original manufacturer, the incentive to provide cheap, low quality copies will be minimized, due to the expense of retooling for each xe2x80x9ckey and lockxe2x80x9d set.
The key system may include many different protrusion and recess structures, for example, tabs and slots (typically thin or elongated bar and channel structures or elongated dove-tail structures), bumps and holes (typically rounded or mounded structures with cooperating valleys or holes), wedges and wedge-shaped wells (typically circular section structures); and many other shapes. If a cartridge must be rotated on its longitudinal axis to be installed in a holder, leeway in the recess structure is supplied so that the protrusion may enter it while the cartridge still has a radial distance to turn. For example, in the case of an elongated filter that is pushed up into a filter head and then rotated on its axis to install its top end into a filter head, the recess comprises an axial portion for allowing axial insertion and a radial portion for radial rotation of the filter cartridge relative to the filter head.
The key system structures are located on surfaces of surfaces of filter cartridges (or xe2x80x9cfiltersxe2x80x9d) and holders that contact each other during connection of the cartridge to the holder. This may be either surfaces that are involved in mainly providing a physical connection between the cartridge and holder or that also are involved in providing a fluid connection between the cartridge and the holder.
An example of key system structure on surfaces that are involved in providing physical connection, rather than fluid connection, is the key system structure on a shoulder of a filter cartridge that fits up into a valve-head holder. These areas are surfaces that do not normally liquid-seal to each other, but must clear each other if the end of the filter cartridge is to fit up inside the interior cavity of the valve-head. The top circumferencial shoulder of the filter cartridge and the inner surface of a valve-head, typically have areas that come in very close contact, but that are not directly involved in forming a liquid seal between the cartridge and the valve-head. These non-liquid-sealing areas may be keyed so that only a cartridge with a certain keyed surface shape may extend far enough up into the valve-head to be installed and locked into place. For example, tabs or other protrusions may be provided on the top surface of a filter spaced outward from an inlet-outlet neck, but external to the liquid-receiving passages. These filter cartridge protrusions may mate or xe2x80x9cnestxe2x80x9d in identically-located recesses on the inside surface of the valve-head that receives the cartridge, wherein the valve-head recesses are also external to the cartridge/valve-head liquid-receiving passages.
The keyed structure on the filter shoulder and the inner surface of the valve-head holder may be said to be located around the outer circumference of a shoulder of the top end of the filter cartridge and the cooperating or corresponding inner circumference of the valve-head cavity. Preferably the protruding xe2x80x9ckeyxe2x80x9d structure comprises a plurality of protrusions located within an arc of about 90 degrees or less around the circumference on which it lies, or more preferably within about 70 degrees or less. The cooperating recess structure is preferably located in the cavity surfave, facing the filter cartridge shoulder, and, likewise, the same number of recesses are located within the same amount of circumference, preferably about 90 or less, and, more preferably, about 70 degrees or less. In this type of embodiment, the protruding and recessed structures do not form a liquid seal(s) between the filter cartridge and the valve-head, because other structure typically nearer the central axis of the filter cartridge and head serve that purpose. While this preferred key system locates the protrusions on the filter cartridge shoulder and the recesses on the head, the opposite is envisioned, wherein the protrusions may be inside the filter head and the recesses may be on the filter cartridge.
Another type of embodiment of the keyed system involves the structure that create a fluid seal between the filter cartridge and the holder, for example, the inlet and outlet ports of the filter cartridge and the respective, cooperating ports/tubes in the holder that convey liquid to and from the cartridge. In this type of embodiment, the protruding and recessed structures are located around the inner and outer circumference of a tubular connector, comprising a male tube and female receiver, that allow connection of the filter cartridge and the holder, wherein fluid is conducted through the tubular conductor(s) once the cartridge seals to the holder. An example of such a tubular connector key system includes one in which both the filter holder""s inlet and outlet and both the filter cartridge""s inlet and outlet are all tubular and are all keyed. For example, a filter holder""s inlet tube and an outlet tube (that direct flow to a cartridge and from the cartridge, respectively) each have an elongated axial tab that protrudes out from the outer cylindrical surface of the inlet tube and outlet tube at a chosen circumferential (also called xe2x80x9cradialxe2x80x9d or xe2x80x9cangularxe2x80x9d to imply non-axial) location or locations (that is, at different places on the circumference of the tube surfaces). Likewise, the inner cylindrical surfaces of the cartridge""s cooperating female tubes (into which the holder inlet tube and outlet tube slide and seal) have channels or xe2x80x9cslotsxe2x80x9d recessed into the surfaces at corresponding circumferential positions. This way, the holder inlet and outlet tubes slide into the cartridge ports, with the holder tabs sliding into the cartridge slots without significant resistance. Another cartridge with slots at a different circumferential location, on either one its ports, would not receive the holder tubes and, hence, could not be accidentally or incorrectly installed in that particular holder. In such a case, where the filter cartridge has two tubes (inlet and outlet ports), each of the ports could have a different slot circumferential location, as long as the holder is made to match. For example, the holder""s inlet tube tab (and corresponding slot on the cartridge inlet port) could be at xe2x80x9cstraight upxe2x80x9d at 0 degrees, while the tab on the holder""s outlet tube (and corresponding slot on the cartridge outlet port) could be at 30 degrees offset relative to the inlet tabs and slots. With this type of system, for example, varying additional different cartridge and holder sets each by an additional 30 degrees, many different sets of keyed cartridges and cooperating holders may be made. Many other amounts besides 30 degrees could be chosen, but this amount of offset gives many different combinations while providing an offset easily seen and judged by a person. The inlet tabs and slots and the outlet tabs and slots may be varied the independently, for example, many sets may have the inlet tabs and slots at zero (0) degrees, while the sets may have differently-positioned outlet tabs and slots. Or, sets may have inlet tabs and slots that vary from set to set by 10 degrees, while those sets"" outlet tabs and slots may vary by 15 degrees, for example. The mathematics of such a system suggest that practically an xe2x80x9cendlessxe2x80x9d number of sets with different key system structures may be designed.
Other key system styles are envisioned, which allow generally flat or smooth surfaces of the filter cartridge and the holder that conventionally would contact each other to instead include a key system structure that ensures that only a particular type of filter cartridge may be installed in a particular holder. The key system structure of the various sets of filter cartridge and cooperating holders/valve-heads is typically invisible once the filter cartridge is installed. While this may result in differently-keyed filter cartridges having substantially similarly-shaped outer housings, a manufacturer may include indicia on the outer surface of the filter cartridge to indicate the different media or other filter differences. Also, a user may look at the key system structure as long as the filter cartridge is uninstalled. In any event, when the user attempts to install a cartridge, only properly-keyed cartridges can be installed into the holder/valve-head/manifold.
By xe2x80x9cholderxe2x80x9d is meant any of a variety of devices that receive and seal to a replaceable filter or filter cartridge. This can include a valve head (including valving to shut off piping when the cartridge is removed), a filter bracket that supports the cartridge and provides fluid flow conduits into and out of the cartridge, and other devices that contact and are in fluid communication with the cartridge.
By xe2x80x9cfilterxe2x80x9d or xe2x80x9cfilter cartridgexe2x80x9d is meant any container of filtration or treatment media that is connected to a holder for fluid communication with the holder to filter and/or treat the fluid brought into it via the holder. The keyed system invention may be applied to whatever structure of a filtering unit is inserted into the head or other holder, which might be a unitary filter or a filter cartridge encased partially in an outer housing below the level where the filter cartridge engages in the head.